sigillum

Sigillum is a Latin term meaning seal or signet. In historical and scholarly usage, it refers to both the physical object used to authenticate documents and the impression it leaves. A sigillum functions as a signature substitute, signaling authority and legitimacy for the issuer.

Practically, a seal is created with a signet matrix, a metal device bearing a heraldic emblem, monogram, or other insignia. The matrix is pressed into soft media such as wax, clay, or parchment to leave a durable imprint. Seals were often hung from cords or attached to documents, serving to secure folds and provide evidence that the contents had not been opened or altered since sealing. The impressions could vary in design, language, and form, including round or square shapes and inscriptions in Latin or local scripts.

Historical usage encompasses ancient, medieval, and early modern administrations. In ancient Rome, officials used seals to authorize decrees and correspondences. In medieval and early modern Europe, kings, princes, bishops, and cities employed seals to authenticate charters, proclamations, and legal instruments. The papal chancery and other ecclesiastical offices maintained formal seal traditions as part of governance and communication, with each issuer possessing distinct sigilla.

In contemporary scholarship, sigillum remains a conventional term for the seal or its impression, though in everyday English the objects are more commonly called seals or signets. The concept has also influenced related terms; in esoteric traditions, the word sigil—bearing a separate set of practices—derives from the same Latin root.